Pleated-side bag or sack made of flexible, weldable material

ABSTRACT

A pleated-side bag or sack of flexible weldable material with a closed bottom end and a top end provided with an internal reclosing device has side pleats inserted V-wise between two bag walls forming a front wall of the bag and a back wall of the bag. The pleats extend from a bottom end to a top end. A reclosing device is formed by two pressure sealing strips below the top end. The two pressure sealing strips are formed by two hook-and-loop strips of weldable material which are fastened in parallel alignment opposite one another on the two bag walls, occupying substantially an entire interior bag width, and the side pleats project with their two V-panels between the hook-and-loop strips into the bag interior.

[0001] The invention relates to a pleated-side bag or sack of flexible,weldable material having a closed bottom end and a top end provided withan internal reclosing device, the sides inserted in V-shape between thetwo walls, which form the front wall and the back wall of the bagrunning continuously from the bottom end to the top end, and thereclosing device being formed by two pressure-sealing strips, which canbe brought into mutual closing engagement under the top end.

[0002] Side-pleating bags or sacks of this kind are used for packingdifferent materials in pieces, grains or powders which, after theremoval of the end closure, for example, a weld seam, are taken out as arule in portions. The reclosing device makes it possible for the user toreclose the bag or sack after each removal of its contents or to open itagain.

[0003] Side-pleating bags, in which the pressure closure strips of thereclosing device are formed by two strips, which can be brought togetheras tongue and groove into closing engagement by the application ofpressure, of which the one, for example, the groove strip is fastened toone wall of the bag, and the other, the tongue strip in the examplechosen, to the opposite half of the side-pleat and to the area of theother wall of the bag between these two side pleat halves. The tow otherside pleat halves, which have not received the pressure closure stripare permanently bonded, for example, welded, to the adjacent bag wall.

[0004] Admittedly, by these means, it is possible to reclose the bag orsack after removing contents. However, on the other hand, it isundesirable during the previous removal of contents that the side pleatscannot be spread out completely flat, as would be required for creatingthe large-format opening made possible by the shape of the bag. This isdue to the fact that in each case one half of the side pleats ispermanently bonded to the adjacent bag wall, which results in acorresponding restriction of the opening cross section. In the knowndesigns, the reclosing operation itself is problematical, since it isoften difficult to bring the narrow, rib-like tongue of the one closurestrip together and thus in engagement with the corresponding narrowgroove in the other closure strip.

[0005] The invention addresses the problem of creating a side-pleatedbag or sack of the kind referred to above, which will permit a maximumpossible opening of the bag or sack at the top end for removal ofcontents and in which, at the same time, the reclosing device willassure easy reclosing of the bag or sack after contents have beenremoved.

[0006] This problem is solved by the invention with a configuration ofthe side-pleated bag or sack of claim 1. Since, with this configuration,the two pressure closure strips are fastened in parallel mutualalignment opposite one another at the two walls of the bag and the sidepleats spring forward with their halves or limbs pleated V-wise andthere is no bonding of one side pleat half with a bag or sack wall, bothhalves of the side pleats can be spread apart flatly together unhamperedat the top end to open the bag, so that the largest possible opening ofthe bag is created for the removal of its contents. Designing the twopressure closure strips as hook-and-loop strips greatly also facilitatesreclosure since, as is commonly the case with hook-and-loop closurestrips, a full-surface mutual interlocking can be brought about over theentire width of the closure strips by the application of pressure. Thusthe bag or sack can be reclosed even when the two hook-and-loop stripsto be brought in interlocking engagement are slightly offset from oneanother, which is not the case with tongue-and-groove closures. Ahook-and-loop strip width of about 10 to 20 mm has proven advantageousin this connection.

[0007] Fundamentally, in the scope of the present invention, anyappropriate hook-and-loop closure strips available commercially can beused, both in the classical mode, in which one strip is provided withsmall hooks on its attaching surface, which hook into the tangledsurface of the other strip under pressure, or also in another embodimentfavorable to bag manufacture, in which the hook-and-loop strips havesimilarly configured adherent surfaces with catching means, which can bebrought into interlocking engagement. Such catching means can be in theform of, for example, projections distributed over the attaching surfacewith somewhat mushroom-like thickened heads or shaped in the manner ofdouble cones, which can be brought with the application of pressure intomutual interlocking engagement and can be released again by appropriateapplication of traction.

[0008] Additional features and advantages of the invention will appearin the claims and in the following description, in conjunction with thedrawing, in which a plurality of embodiments of the subject of theinvention are represented schematically. In the drawing:

[0009]FIG. 1 shows a frontal view of the upper portion of aside-pleating bag in the inactive state with a partially cut-away frontwall of the bag,

[0010] FIGS. 2 to 6 are each a cross section taken on line A-A of FIG. 1on a reduced scale in order to show each embodiment of the invention,and

[0011]FIG. 7 shows a view corresponding to FIG. 1 in which, however, thebag is represented in the open state with the side creases spread flat.

[0012] The pleated-side bag represented by way of example in the drawingcan be formed as a plastic bag of a film of thermoplastic material,especially a polyolefin such as polyethylene or polypropylene, or as acompound bag of a compound material, which bears at least, on itsinside, a layer of thermoplastic capable of being welded, while one ormore externally adjoining layers of the compound material can be of adifferent nature. For example, two-layer compound films or laminates ofthermoplastic can be used, it being desirable that the layers to bewelded together during bag manufacture have a lower melting point thanthe outer layer of the material.

[0013] In particular, the bag in the selected example, consisting of asingle plastic film and identified as a whole by the number 1, has asealed bottom end, not shown, made in any practical manner, and a topend 2 which, when the bag 1 is empty as shown in FIG. 2 and, after thebag is filled, is closed with a welded seam along the upper marginaledges 3 of the bag walls 4 and 5, as indicated in FIG. 1 by adash-dotted line 6.

[0014] The bag wall 4 constitutes the front wall of the bag, while bagwall 5 forms the back wall of the bag. Between these, side pleats 7 areinserted on both sides, which extend from the bottom end of bag 1 to itstop end 2 and end flush with the top marginal edges of the bag walls 4and 5.

[0015] At an interval below the later welded seam 6, a reclosing device8 is formed near the top end between the two bag walls 4 and 5 andcomprises two hook-and-loop strips 9 made of weldable material like athermoplastic film, of which the one is welded or heat-sealed or, ifdesired, also cemented to the front wall of the bag and the other isaffixed to the back wall 5 by welding or heat sealing or in some casesby cementing. The hook-and-loop strips are arranged with respect to thecentral axis 10 of bag 1 in a common transverse plane with attachingsurfaces 11, which are opposite one another and can be brought withtheir interlocking surfaces into mutual hooking engagement with oneanother. The reclosing device 8 is used by the consumer after removingthe weld seam 6.

[0016] Each side pleat 7 has on both sides of its central crease 12 twoside-pleat halves 13 and 14, which are joined along lateral weld seams15 and 16 to the front wall 4 and back wall 5, respectively, of the bag.When the bag 1 is empty according to FIGS. 1 to 6, the halves 13 and 14of each side pleat 7 lie flat one on the other V-wise and thus form thepanels of a V projecting freely between the hook-and-loop strips 9 intothe interior of the bag.

[0017] As it can be seen especially in FIGS. 2 to 6, the hook-and-loopclosure strips 9 fastened to the inside of both bag walls 4 and 5 occupyvirtually the entire interior width of the bag and, at the ends, theyare drawn into the weld seams 15, 16, and fused to the material of thebag walls 4 and 5 and side pleats 7 by the welding operation that isperformed. If such fusion into the seams 15 and 16 presents difficultiesbecause, for example, of a higher melting point of the plastic used inthe hook-and-loop strips, the hook-and-loop strips 9 can terminate at ashort distance from the seams 15 and 16.

[0018] In the embodiment of FIG. 2, the side pleats 7 bear nohook-and-loop strips on their inside. A simple embodiment of this kindcan recommend itself when, for example, the side pleats have but aslight depth, so that a closure of the two hook-and-loop strips 9 in thearea between the side pleats 7 then flattened by the application ofpressure may be sufficient. This depends, of course, also on thematerial packed in the bag 1.

[0019] In the embodiment of FIG. 3, the V-panels of the side pleats,that is, the side pleat halves 13 and 14, are provided with alignedpunched holes 17 in a common plane containing the hook-and-loop strips 9of bag walls 4 and 5. Thus, with respect to the example in FIG. 2,additional adherence of the hook-and-loop strip 9 in bag wall 4 to thehook-and-loop strip 9 in bag wall 5 through the punched holes 17 in theside pleats 7 is possible.

[0020]FIG. 4 visualizes an embodiment, in which the V-panels or sidepleat halves 13 and 14 are provided on their inside with hook-and-loopstrips 18 in a common plane containing the hook-and-loop strips 9 of bagwalls 4 and 5, so that their adherent surface 11 is opposite that of thehook-and-loop strips 9. The hook-and-loop strips 18 extend oversubstantially the entire width of the side pleats 7, across the centercreases 12 to the lateral weld seams 15 and 16, but do not reach intothem, in order thus to avoid difficulties in the production of the weldseams 15 and 16 by increasing the number of layers to be welded. Such anembodiment, preferred at this time, permits an especially quick andcomprehensive closure of the bag end by the intermeshing of the hookstrips 9 on the bag walls 4 and 5 with the loop strip 18 on the adjacentside pleat halves 13 and 14 and with one another in the middle areabetween the side pleats 7.

[0021] The embodiment in FIG. 5 differs from the one in FIG. 4 only inthat, instead of the hook-and-loop strips 18 running across the crease12 on the inside of the V-panels or side pleat halves 13 and 14,individual smaller hook-and-loop strips 19 are disposed in dot form, soto speak, on both sides of the inner crease 12 with their catchingsurface 11 opposite the adjacent hook-and-loop strip 9 on the bag walls4 and 5. The adhesion of the top end 2 of bag 1 is accomplished in thiscase in a manner similar to the embodiment in FIG. 4.

[0022] Lastly, FIG. 6 shows an embodiment, in which hook-and-loop strips20 are provided similar to hook-and-loop strips 19 in FIG. 5, but on theoutside of the V-panels or side pleat halves 13 and 14 with their activesurfaces 11 opposite one another. The closure of the top end 2 of bag 1takes place in this case between the outsides of the side pleat halves13 and 14 directly between the hook-and-loop strips 20, and internallythe area between the inner creases 12 of the side pleats 7 by theadherent bond between the hook-and-loop strips 9 on bag walls 4 and 5.

[0023] Whereas in FIGS. 2 to 6, the side pleats 7 with their V-panels 13and 14 are shown, in the interest of clear representation, in anintermediate position between a position flat against one another(closed position) and a flat spread-open position (open position), fromwhich it is apparent that with the side pleats 7 spread out flat, thefull cross section of the mouth of bag 1 can be used for removing thecontents.

1. A pleated-side bag or sack of flexible weldable material with aclosed bottom end and a top end provided with an internal reclosingdevice, wherein side pleats inserted V-wise between the two bag wallsforming the front wall of the bag and the back wall of the bag reach allthe way from the bottom end to the top end and the reclosing device isformed by two pressure sealing strips, which can be brought into mutualclosing engagement below the top end, wherein the two pressure sealingstrips are formed by two hook-and-loop strips (9) of weldable material,which are fastened in parallel alignment opposite one another on the twobag walls (4, 5), occupying substantially the entire interior bag width,and the side pleats (7) project with their two V-panels (13, 14) betweenthe hook-and-loop strips (9) into the bag interior.
 2. The pleated-sidebag or sack of claim 1, wherein the V-panels (13, 14) of the side pleatsare provided with punched holes (17) in a common plane containing thehook-and-loop strips (9) of the bag walls.
 3. The pleated-side bag orsack of claim 1 or 2, wherein the V-panels (13, 14) of the side pleats(7) are provided in turn with hook-and-loop strips (18, 19, 20) in acommon plane containing the hook-and-loop strips (18, 19, 20) in acommon plain containing the hook-and-loop strips (9) of the bag walls(4, 5).
 4. The pleated-side bag or sack of claim 3, wherein thehook-and-loop strips (18) of the V-panels (13, 14) extend substantiallyover the entire width of the side pleats (7).
 5. The pleated-side bag orsack of claim 3, wherein the hook-and-loop strips (19, 20) of theV-panels (13, 14) extend only over a part of the width of each V-panel(13, 14).
 6. The pleated-side bag or sack of claim 5, wherein thehook-and-loop strips (19) are disposed on the inside of the V-panels(13, 14) in a position opposite in each case to a hook-and-loop strip(9) in the bag walls (4, 5).
 7. The pleated-side bag or sack of claim 5,wherein the hook-and-loop strips (20) are disposed on the outer side ofthe V-panels (13, 14) with confronting adhesion surfaces (11).
 8. Thepleated-side bag or sack of any one of the claims 1 to 7, wherein thehook-and-loop strips (9) of the bag walls (4, 5) are drawn in with theirends into side wall welds (15, 16) of the bag (1), which join the sidepleats (7) to the margins of the bag walls (4, 5).
 9. The pleated-sidebag or sack of any one of the claims 1 to 8, wherein the width of thehook-and-loop strips (9, 18-20) is approximately 10 to 20 mm.
 10. Thepleated-side bag or sack of any one of the claims 1 to 9, wherein thehook-and-loop strips (9, 18-20) have similarly shapes adherence surfaces(11) with catch members, which can be brought into mutual interlockingengagement.